Add UX hint that repos are being added

Created by: ryanslade

After adding repos as a user you are redirected to your repositories list page, something like https://sourcegraph.com/users/USERNAME/settings/repositories

However, since repos are being added in the background it's possible for the newly added repos not to appear in the list yet or even for the list to be empty.

It's not obvious at this point that anything is happening and that the only way to check for repos is to refresh the page.

I'm not sure what the best approach is here from a UX perspective, @quinnkeast WDYT?